Experiment Station Beport. 23 



ON FEEDING EXPEEIMENTS. 



C. A. GOESSMANN. 



Careful investigations in stock-feeding have taught us les- 

 sons similar to those we have learned to appreciate in feed- 

 ing plants, or in the cultivation and the production of farm 

 crops. All our form plants need nitrogen, phosphoric and 

 sulphuric acids, potassa, soda, lime, magnesia and iron ; yet 

 not two species of plants have been found, which need the 

 same quantity of these substances, during their entire period 

 of life, nor at any stage of their growth. No one of the 

 above-stated essential mineral constituents of plants can re- 

 place another one to any extent without altering the charac- 

 ter of the plant, or even endangering its life. Potassa 

 cannot take the place of lime, nor phosphoric acid that of 

 sulphuric acid. When lime is needed, a shovelful of that 

 substance is worth more than any quantity of the many times 

 more expensive potassa. That particular mineral element 

 which supplies an actual want of the soil is, for this reason, 

 from a physiological standpoint, considered the most impor- 

 tant one for the production of the plant ; for without it the 

 remaining essential mineral constituents of plants, whatever 

 their quantity may be, cannot make them grow. 



In regard to the growth and the support of our farm live 

 stock, similar relations have been noticed. Actual feeding 

 experiments have shown that three groups of plant con- 

 stituents (nitrogenous, non-nitrogenous, and mineral con- 

 stituents) are required to sustain successfully animal life. 

 No one or two of them, alone, can support it for any length 

 of time. In case the food does not contain digestible non- 

 nitrogenous substances, the fat and a part of the muscles of 

 the animal on trial will be consumed in the support of respi- 



